Pscheoverdrive

Alright, so I've been digging through the archives and Wiki (technical, aren't I?) since thinking that I should get an oil catch can.

WELL, as I'm sure a bunch of you know, it seem like everyone's got different opinions on this and runs a different setup.

2.0GT35, A400 and some others run their oil catch cans vented... And that seems to make sense. Lots of boost, no chance of oil getting back into the intake. But, Pac's pics of his valve cover after removing his PCV system were pretty ugly... And I also wonder about a few things with venting the catch can:
1. If the can does not go back to the intake, I'm assuming you're relying on positive pressure in the intake track to purge the crankcase of blow by? If so...
2. If that air is not recirculated, does this equate to a small 'boost leak'... Meaning, not all the air your turbo is working so hard to bring in is being combusted? If so...
3. Would this screw with your ECU on a car that still has a MAF?

And then...
4. With a PCV delete, what do you use to purge the crankcase? Kinda confused on ppl's setups when it comes to that. I know Roger has a block-off plate, but he's not really getting rid of the whole system, is he?



The reason I bring this up is that I'm putting in a GT2871 Elim (yeah, it finally came!) in the near future, and an oil catch can certainly won't hurt. I was going to replace my PCV valve, but now I'm not sure. Right now, my thoughts are to run a catch can closed and run back to the intake. Thoughts?



Also, to A400:
If you're having trouble with oil 'puke' from your catch can, why not run two? Run a non-vented one, like the 034 Vortex, into another vented one. The first can would catch liquid oil and some of condense some of the vapors, while the second would condense the rest and vent. Just an idea... I doubt oil would fly through both cans like that.

A400

Psyche

"2.0GT35, A400 and some others run their oil catch cans vented... And that seems to make sense. Lots of boost, no chance of oil getting back into the intake. But, Pac's pics of his valve cover after removing his PCV system were pretty ugly...

> put my filter on catch can, not on the cover, the distance will make a difference<
And I also wonder about a few things with venting the catch can:

1. If the can does not go back to the intake, I'm assuming you're relying on positive pressure in the intake track to purge the crankcase of blow by? If so...

> I drain the oil back into the crankcase, dry sump suction helps when running and gravity after engine off. Be sure and put a 1 waqy valve on line going into crankcase - dont want to blow oil vapor in from bottom end.<

2. If that air is not recirculated, does this equate to a small 'boost leak'... Meaning, not all the air your turbo is working so hard to bring in is being combusted? If so...

> not a part of intake air anymore so no reason to go back into intake if not concerned over emissions (I am not convinced that the raw vapor is as toxic as burned oil. But bottom line all is good with not taking back into intake tract, besides a better description of the can is an oil seperator, it just seperates the air from the oil<

3. Would this screw with your ECU on a car that still has a MAF?

> No, this would be 'lost air' and the ECU doesnt expect to see it again<
And then...

4. With a PCV delete, what do you use to purge the crankcase? Kinda confused on ppl's setups when it comes to that. I know Roger has a block-off plate, but he's not really getting rid of the whole system, is he?

> you are not recirculating the air, as long as all crank venting is routing to the can, you are eliminating the PCV <

The reason I bring this up is that I'm putting in a GT2871 Elim (yeah, it finally came!) in the near future, and an oil catch can certainly won't hurt. I was going to replace my PCV valve, but now I'm not sure. Right now, my thoughts are to run a catch can closed and run back to the intake. Thoughts?

> Looks good, but forget about running to intake. If can is running properly you will just be seperating oil from air and then draining the liquid back to the can. At that point air should be more or less free of oil droplets. I dont even consider this pollution unless excessive mist starts coming off of engine<

Also, to A400:
If you're having trouble with oil 'puke' from your catch can, why not run two? Run a non-vented one, like the 034 Vortex, into another vented one. The first can would catch liquid oil and some of condense some of the vapors, while the second would condense the rest and vent. Just an idea... I doubt oil would fly through both cans like that.

> Actually it is a small amount and not really worth fooling with. Most is just seepage when filter is saturated. Takes 2 seconds to wipe oil off. If I would ever clean the filter it would quit for a long while, this isnt a real problem now.<

Pscheoverdrive

Very thorough! Thanks... You've answered all my questions well.